An outbreak investigation of influenza B in the boarding school, Takuapa district, Phang nga Province, Thailand, 17–29 January 2018

Abstract

Background: On 17th January 2018, the Phang nga Provincial Health team was notified about a cluster of influenza–like illness in the boarding school of Takuapa district. Then we conducted the outbreak investigation in order to confirm the diagnosis and the outbreak, to know the distribution of the outbreak and to give the recommendations for disease control measures.
Methods: Descriptive study were performed by reviewing medical records, interviewing the patients, finding the active case in the community and collecting the specimens for RT–PCR. The environmental survey was also conducted in the school.
Results: Among total 685 persons in this school, 219 cases got sick with the attack rate of 31.97%. Cases were identified in all classrooms and dormitories. For classrooms, room 3/1, room 2/3 had highest attack rate which were 69.23% and 62.50%, respectively. For the dormitories, Phor–Pau–rau–2 and Pingkan 2 had highest attack rate which were 61.76% and 60.61%, respectively. Top three common symptoms were cough (81.74%), sore throat (60.82%) and running nose (34.42%). The RT–PCR was positive for Influenza B in 4 cases.
Discussions: This was the Influenza B outbreak in the boarding school setting. It was the propagated outbreak that occurred in all classrooms and dormitories. The cross infection between different classrooms and dormitories was observed. The important risk factors were such as 1) the school festival during National children’s day, 2) the overcrowding of school dormitories, 3) the inappropriate personal hygiene of the students and 4) the closed contact behaviour among the students. The key of success in disease control were such as 1) to conduct the outbreak investigation and the control measures in time, 2) the good cooperation from the school personnel during the surveillance process, 3) the isolation of sick students in the separated dormitory and 4) allow the sick students to drop out of school. Recommendations: 1) Set the disease surveillance system in the school and 2) Give health education to the students in order to change their health behavior.